Right-hemispheric homotopic circuits for language at single-neuron resolution

Language is the bedrock of human civilization. It shapes how we connect, communicate and collaborate, and how we think, feel and experience. Language is typically viewed as a left-brain function. In contrast, the role of the right brain in language processing is unclear and heavily contested. Compelling evidence suggests that the right hemisphere harbors a language system that is mirror-symmetric to the left and contributes to the reorganization of language functions after brain injury. However, because conventional neuroimaging and non-invasive electrophysiology do not have the necessary spatiotemporal resolution, the cellular and circuit mechanisms are unknown. My key objective is to provide the first investigation of right-hemispheric language processing at single-neuron resolution with coverage of multiple interconnected cortical hubs that serve linguistic and non-linguistic cognitive functions. I will address two central questions. First, how do individual neurons, neuronal populations and their circuits in right brain regions homotopic to the left language regions contribute to our ability to comprehend and produce language? My team and I will perform large-scale recordings from right-hemispheric microelectrode arrays implanted chronically in individuals with left-sided stroke that has compromised some, but not all linguistic skills. This will allow us to describe in unprecedented detail the right-hemispheric engagement in normal and impaired language functions. Second, can we target this right-sided network to drive language recovery after brain injury? My team and I will engineer the investigated circuits using closed-loop neurofeedback and intracortical microstimulation to explore their potential for treating acquired disorders of language. RHETORICAL will bring together my unique expertise in neurology, neuroscience and neurotechnology to propel forward our mechanistic understanding of this singularly and quintessentially human cognitive function.